Stimuli-responsive synthetic helical polymers.

Synthetic dynamic helical polymers (supramolecular and covalent) and foldamers share the helix as a structural motif. Although the materials are different, these systems also share many structural properties, such as helix induction or conformational communication mechanisms. The introduction of stimuli responsive building blocks or monomer repeating units in these materials triggers conformational or structural changes, due to the presence/absence of the external stimulus, which are transmitted to the helix resulting in different effects, such as assymetry amplification, helix inversion or even changes in the helical scaffold (elongation, J/H helical aggregates). In this review, we show through selected examples how different stimuli (e.g., temperature, solvents, cations, anions, redox, chiral additives, pH or light) can alter the helical structures of dynamic helical polymers (covalent and supramolecular) and foldamers acting on the conformational composition or molecular structure of their components, which is also transmitted to the macromolecular helical structure.

The function of prolonged copulations in Enchenopa treehoppers (Hemiptera: Membracidae).

Copulations are very brief in many species, sometimes taking only seconds, but in other species they can be quite prolonged. Potential explanations for prolonged copulations include time requirements for the transfer of sperm and/or other ejaculate substances. Ejaculate substances could function to regulate female receptivity to subsequent matings, provide nutritional nuptial gifts, or hasten egg oviposition at a potential survival cost to the female. We investigated prolonged copulation in a member of the Enchenopa binotata complex of treehoppers (Hemiptera: Membracidae), in which females rarely remate and copulation can last several hours. We assigned females to treatments in which we interrupted copulation at different times. We also included a control where copulation was not interrupted. We found that females that experienced shorter copulations were more likely to be subsequently receptive to an attractive male. We also found that few females produced offspring when they engaged in short copulations compared to those with longer copulations. We did not find any differences in female survival. Our results support the sperm transfer and receptivity regulation hypotheses. We discuss potential reasons for why these processes should take so long in a species with low female remating.

On the function of a female-like signal type in the vibrational repertoire of Enchenopa male treehoppers (Hemiptera: Membracidae).

Animals often mimic the behaviours or signals of conspecifics of the opposite sex while courting. We explored the potential functions of a novel female-like signal type in the courtship displays of male Enchenopa treehoppers. In these plant-feeding insects, males produce plant-borne vibrational advertisement signals, to which females respond with their own duetting signals. Males also produce a signal type that resembles the female duetting responses. We experimentally tested whether this signal modifies the behaviour of receivers. First, we tested whether the female-like signal would increase the likelihood of a female response. However, females were as likely to respond to playbacks with or without them. Second, we tested whether the female-like signal would inhibit competing males, but males were as likely to produce displays after playbacks with or without them. Hence, we found no evidence that this signal has an adaptive function, despite its presence in the courtship display, where sexual selection affects signal features. Given these findings, we also explored whether the behavioural and morphological factors of the males were associated with the production of the female-like signal. Males that produced this signal had higher signalling effort (longer and more frequent signals) than males that did not produce it, despite being in worse body condition. Lastly, most males were consistent over time in producing the female-like signal or not. These findings suggest that condition-dependent or motivational factors explain the presence of the female-like signal. Alternatively, this signal might not bear an adaptive function, and it could be a way for males to warm up or practice signalling, or even be a by-product of how signals are transmitted through the plant. We suggest further work that might explain our puzzling finding that a signal in the reproductive context might not have an adaptive function.

Proposed minimal standards for description of new taxa of the class Halobacteria.

Halophilic archaea of the class Halobacteria are the most salt-requiring prokaryotes within the domain Archaea. In 1997, minimal standards for the description of new taxa in the order Halobacteriales were proposed. From then on, the taxonomy of the class Halobacteria provides an excellent example of how changing concepts on prokaryote taxonomy and the development of new methods were implemented. The last decades have witnessed a rapid expansion of the number of described taxa within the class Halobacteria coinciding with the era of genome sequencing development. The current members of the International Committee on Systematics of Prokaryotes Subcommittee on the Taxonomy of Halobacteria propose these revisions to the recommended minimal standards and encourage the use of advanced technologies in the taxonomic description of members of the Halobacteria. Most previously required and some recommended minimal standards for the description of new taxa in the class Halobacteria were retained in the present revision, but changes have been proposed in line with the new methodologies. In addition to the 16S rRNA gene, the rpoB' gene is an important molecular marker for the identification of members of the Halobacteria. Phylogenomic analysis based on concatenated conserved, single-copy marker genes is required to infer the taxonomic status of new taxa. The overall genome relatedness indexes have proven to be determinative in the classification of the taxa within the class Halobacteria. Average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity values should be calculated for rigorous comparison among close relatives.

Clusters of cognitive performance predict long-term cognitive impairment in elderly patients with subjective memory complaints and healthy controls.

INTRODUCTION: Patients with subjective memory complaints (SMC) may include subgroups with different neuropsychological profiles and risks of cognitive impairment. METHODS: Cluster analysis was performed on two datasets (n: 630 and 734) comprising demographic and neuropsychological data from SMC and healthy controls (HC). Survival analyses were conducted on clusters. Bayesian model averaging assessed the predictive utility of clusters and other biomarkers. RESULTS: Two clusters with higher and lower than average cognitive performance were detected in SMC and HC. Assignment to the lower performance cluster increased the risk of cognitive impairment in both datasets (hazard ratios: 1.78 and 2.96; Plog-rank: 0.04 and <0.001) and was associated with lower hippocampal volumes and higher tau/amyloid beta 42 ratios in cerebrospinal fluid. The effect of SMC was small and confounded by mood. DISCUSSION: This study provides evidence of the presence of cognitive clusters that hold biological significance and predictive value for cognitive decline in SMC and HC. HIGHLIGHTS: Patients with subjective memory complaints include two cognitive clusters. Assignment to the lower performance cluster increases risk of cognitive impairment. This cluster shows a pattern of biomarkers consistent with incipient Alzheimer's disease pathology. The same cognitive cluster structure is found in healthy controls. The effect of memory complaints on risk of cognitive decline is small and confounded.

Variability of clinical practice in the care of the second stage of labor among midwives in Spain.

BACKGROUND: There are recommendations based on scientific evidence on care in the second stage of labor, but it is not known to what degree the professionals comply with these recommendations. OBJECTIVE: The aim of this study is to examine the variability in clinical practices among midwives during the second stage of labor, including positions, mobility, practices, and the maximum time allowed before initiating active pushing, and to assess their adherence to clinical practice guidelines. METHODS: A cross-sectional observational study. A self-designed questionnaire was developed and distributed online through scientific societies. The main variables studied were professional and work environment characteristics, maternal positions and mobility, practices during this stage, maximum time to start active pushing and duration of the second stage of labor. Descriptive statistics were calculated using SPSS 24.0. RESULTS: Regarding the woman's position during childbirth, 80.3% (245) of midwives frequently or always allow the woman to choose her birthing position. Furthermore, 44.6% (136) of professionals prefer using side-lying positions for the mother. Regarding drinking fluids during childbirth, 51.1% (156) of midwives allowed the woman to drink the amount of liquids she wanted, whereas 11.1% (34) said that they would allow them to do so however, this was against the protocol of their hospital. When inquiring about the Kristeller maneuver, it was reported to be excessively performed in 35.1% (107) of cases for fetal bradycardia, 33.1% (101) for maternal exhaustion, and 38.4% (117) to avoid instrumental birth. Finally, a great variability was observed in the time criteria used for the initiation of active pushing and the maximum duration of the second stage of labor. CONCLUSIONS: Certain practices, such as the Kristeller maneuver, are overused among midwives, with great variability in the use of certain procedures, the waiting times to initiate pushing and completion of the second stage of labor. Further training and awareness campaigns are needed for professionals to apply evidence-based care.

Duodenal lymphangiomas: endoscopic ultrasound features.

The increasing number of endoscopic explorations help recognize rare lesions of the gastrointestinal tract, such as lymphangiomas, rare benign vascular tumours in adults. Patients with lymphangioma are generally asymptomatic but if complications arise, the approach is endoscopic or surgical. Endoscopic ultrasound aids in distinguishing this tumour from other subepithelial lesions. We present the case of a patient who underwent upper endoscopy and endoscopic ultrasound with findings of two duodenal lymphangiomas.

Iatrogenic rectal perforation due to application of topical treatment in a patient with ulcerative colitis: a rare complication.

Rectal perforations due to topical treatments (enemas or foams) are unusual complications and they have been mostly reported in the use of barium enemas or in elderly patients with constipation. Very little has been reported about perforations secondary to topical treatment in patients with ulcerative colitis. We present the case of a patient with ulcerative colitis who suffered a rectal perforation complicated with a superinfected collection after the application of topical mesalazine foam.

Helical Bilayer Nanographenes: Impact of the Helicene Length on the Structural, Electrochemical, Photophysical, and Chiroptical Properties.

Helical bilayer nanographenes (HBNGs) are chiral π-extended aromatic compounds consisting of two π-π stacked hexabenzocoronenes (HBCs) joined by a helicene, thus resembling van der Waals layered 2D materials. Herein, we compare [9]HBNG, [10]HBNG, and [11]HBNG helical bilayers endowed with [9], [10], and [11]helicenes embedded in their structure, respectively. Interestingly, the helicene length defines the overlapping degree between the two HBCs (number of benzene rings involved in π-π interactions between the two layers), being 26, 14, and 10 benzene rings, respectively, according to the X-ray analysis. Unexpectedly, the electrochemical study shows that the lesser π-extended system [9]HBNG shows the strongest electron donor character, in part by interlayer exchange resonance, and more red-shifted values of emission. Furthermore, [9]HBNG also shows exceptional chiroptical properties with the biggest values of gabs and glum (3.6 × 10-2) when compared to [10]HBNG and [11]HBNG owing to the fine alignment in the configuration of [9]HBNG between its electric and magnetic dipole transition moments. Furthermore, spectroelectrochemical studies as well as the fluorescence spectroscopy support the aforementioned experimental findings, thus confirming the strong impact of the helicene length on the properties of this new family of bilayer nanographenes.

Social Plasticity Enhances Signal-Preference Codivergence.

AbstractThe social environment is often the most dynamic and fitness-relevant environment animals experience. Here we tested whether plasticity arising from variation in social environments can promote signal-preference divergence-a key prediction of recent speciation theory but one that has proven difficult to test in natural systems. Interactions in mixed social aggregations could reduce, create, or enhance signal-preference differences. In the latter case, social plasticity could establish or increase assortative mating. We tested this by rearing two recently diverged species of Enchenopa treehoppers-sap-feeding insects that communicate with plant-borne vibrational signals-in treatments consisting of mixed-species versus own-species aggregations. Social experience with heterospecifics (in the mixed-species treatment) resulted in enhanced signal-preference species differences. For one of the two species, we tested but found no differences in the plastic response between sympatric and allopatric sites, suggesting the absence of reinforcement in the signals and preferences and their plastic response. Our results support the hypothesis that social plasticity can create or enhance signal-preference differences and that this might occur in the absence of long-term selection against hybridization on plastic responses themselves. Such social plasticity may facilitate rapid bursts of diversification.

Weakly Self-Assembled [6]Helicenes: Circularly Polarized Light and Spin Filtering Properties.

Self-assembling features, chiroptical activity, and spin filtering properties are reported for 2,15- and 4,13-disubstituted [6]helicenes decorated in their periphery with 3,4,5-tris(dodecyloxy)-N-(4-ethynylphenyl)benzamide moieties. The weak non-covalent interaction between these units conditions the corresponding circularly polarized luminescence and spin polarization. The self-assembly is overall weak for these [6]helicene derivatives that, despite the formation of H-bonding interactions between the amide groups present in the peripheral moieties, shows very similar chiroptical properties both in the monomeric or aggregated states. This effect could be explained by considering the steric effect that these groups could generate in the growing of the corresponding aggregate formed. Importantly, the self-assembling features also condition chiral induced spin selectivity (CISS effect), with experimental spin polarization (SP) values found between 35-40 % for both systems, as measured by magnetic-conducting atomic force microscopy (AFM) technique.

Diastereomeric multi-chiral pendant groups: Their key role in stimuli-responsive polymeric responses.

Chiral information transmission in helical polymers bearing multi-chiral pendant groups is usually determined by the absolute configuration of the first chiral center. The second chiral residue usually has low-to-null influence in the macromolecular handedness of the polymer, due to its remote position respect to the polyene main chain. Here, we demonstrate how the stimuli responsive properties of diastereomeric polymers, obtained by changing the absolute configuration of the second chiral center, are different due to the unlike properties of diastereoisomers.

Effects of MIdazolam versus MOrphine in acute cardiogenic pulmonary edema and chronic obstructive pulmonary disease: An analysis of MIMO trial.

AIMS: Chronic obstructive pulmonary disease (COPD) is an important comorbidity in heart failure. The MIMO trial showed that patients with acute cardiogenic pulmonary edema (ACPE) treated with midazolam had fewer serious adverse events than those treated with morphine. In this post hoc analysis, we examined whether the presence/ absence of COPD modifies the reduced risk of midazolam over morphine. METHODS: Patients >18 years old clinically diagnosed with ACPE and with dyspnea and anxiety were randomized (1:1) at emergency department arrival to receive either intravenous midazolam or morphine. In this post hoc analysis, we calculated the relative risk (RR) of serious adverse events in patients with and without COPD. Calculating the CochranMantel-Haenszel interaction test, we evaluated if COPD modified the reduced risk of serious adverse events in the midazolam arm compared to morphine. RESULTS: Overall, 25 (22.5%) of the 111 patients randomized had a history of COPD. Patients with COPD were more commonly men with a history of previous episodes of heart failure, than participants without COPD. In the COPD group, the RR for the incidence of serious adverse events in the midazolam versus morphine arm was 0.36 (95%CI, 0.1-1.46). In the group without COPD, the RR was 0.44 (95%CI, 0.22-0.91). The presence of COPD did not modify the reduced risk of serious adverse events in the midazolam arm compared to morphine (p for interaction =0.79). CONCLUSIONS: The reduced risk of serious adverse events in the midazolam group compared with morphine is similar in patients with and without COPD.

Predictors of voice therapy efficacy in vocal cord dysfunction at a tertiary care center.

OBJECTIVE: Vocal cord dysfunction is inappropriate adduction of vocal cords during inspiration that causes dyspnea and is commonly mistaken for exercise-induced asthma. To improve diagnostic accuracy, this study aims to identify demographics associated with vocal cord dysfunction and to determine their impact on the efficacy of voice therapy in improving vocal cord function. STUDY DESIGN: Retrospective chart review. SETTING: Single tertiary care institution between January 2015 and December 2021. METHODS: 184 patients who underwent voice therapy for vocal cord dysfunction were included. The primary outcome was patient self-reported percent improvement of symptoms. The secondary outcome was number of voice therapy treatments. RESULTS: The mean duration of symptoms was 2 ± 3 years. The mean number of voice therapy treatments was 2.2 ± 1.5. Of the 107 (58.2 %) patients with documented perceived breathing improvement percentages recorded, the mean maximal percent improvement was 72.5 ± 21.5 %. Mean maximal percent improvement of symptoms increased with each voice therapy treatment (p = 0.01). This association remained significant when controlling for comorbid conditions such as allergic rhinitis with postnasal drip, anxiety, asthma, and gastroesophageal reflux disease in multivariate analysis (p = 0.005). Patients with asthma had significantly higher maximum percent breathing improvement compared to those without asthma (p = 0.026). Similarly, patients who played sports had significantly higher maximum percent breathing improvement compared to those who did not (p = 0.022). CONCLUSION: Patient perceived breathing improvement with voice therapy is higher among those with concomitant asthma and those who play sports. Voice therapy is a safe and effective first line treatment of vocal cord dysfunction even when controlling for comorbid conditions.

Training and competence in Digestive Endoscopy: Statement Position Paper from the Spanish Society of Digestive Diseases.

Gastrointestinal (GI) Endoscopy is a basic competence for the management of gastrointestinal diseases. However, it should not be regarded as an independent training technique. Rather it is a part of a continuous and accredited process that requires clinical knowledge from the gastroenterologist to keep skills up-to-date in a constantly evolving medical subspecialty. Thus, the only official accredited way for training in GI endoscopy is through the Specialized Health Training program in the Management of the Digestive Diseases administered by the Spanish Ministry of Health.

Spontaneously ruptured hepatocellular carcinoma on non-cirrhotic liver: A prospective case series.

BACKGROUND AND AIMS: Spontaneous ruptured hepatocellular carcinoma is an uncommon complication, and there are scarce data about non-cirrhotic patients. Tumor treatment is not standardized and the risk of peritoneal dissemination is unclear. AIM: we analyzed the treatment and survival in patients with rHCC on non-cirrhotic liver. METHODS: One hundred and forty-one non-cirrhotic patients with hepatocellular carcinoma diagnosed by histology were included in a multicenter prospective registry (2018-2022). Seven of them (5%) presented with hemoperitoneum due to spontaneous rupture. RESULTS: Liver disease was associated in three patients (42.9%). A single nodule was detected in three cases (42.9%). One patient had vascular invasion and none extrahepatic spread. Initial hemostatic therapy and sequential treatment was individualized. Patients with single nodule were treated: resection (one case) with recurrence at 4 months treated with TACE and sorafenib. TACE/TAE followed by surgery (two cases) one in remission 43 months later, the other had liver recurrence at 18 months and was transplanted. Patients with multiple lesions were treated: TAE/emergency surgery and subsequent systemic therapy (two cases), one received lenvatinib (1-year survival) and the other sorafenib (5-month survival). TAE and surgery with subsequent systemic therapy (one case). Initial hemostatic surgery, dying on admission (one case). No patient developed intraperitoneal metastasis. All patients with multiple lesions died by tumor. The 3-year survival rate was 42.9%. CONCLUSIONS: Initial hemostasis was achieved in all patients by TAE/TACE or surgery. Subsequent treatment was individualized, based on tumor characteristics, regardless of rupture. Long-time remission could be achieved in single nodule patients.

Conformational Kinetics in Chiral Poly(diphenylacetylene)s: A Dynamic P/M Memory Effect.

Dynamic P/M (plus/minus) helical memory in chiral dissymmetric poly(diphenylacetylene)s (PDPA) is shown using a PDPA that bears the benzamide of (L)-alanine methyl ester as pendant. For a single chiral polymer, it is possible to obtain either P or M helical structures in a specific solvent without the presence of any chiral external stimuli. To do that, it is necessary to combine the conformational control at the pendant group with a high steric hindrance at the backbone. In this case, by thermal annealing in low-polar solvents, an anti-conformer is stabilized at the pendant which commands a P helix in the PDPA. Next, solvent removal followed by addition of a polar solvent such as dimethyl sulfoxide (DMSO), results in the kinetic conformationally trapped P helix. However, in this medium, the preferred handedness and the thermodynamic macromolecular helix for poly-(L)-1 is M. This process also occurs in the opposite way. Electronic circular dichroism (ECD) and circularly polarized luminescence (CPL) studies show that the dynamic memory effect is present both in ground and excited states.

Mutual Monomer Orientation To Bias the Supramolecular Polymerization of [6]Helicenes and the Resulting Circularly Polarized Light and Spin Filtering Properties.

We report on the synthesis and self-assembly of 2,15- and 4,13-disubstituted carbo[6]helicenes 1 and 2 bearing 3,4,5-tridodecyloxybenzamide groups. The self-assembly of these [6]helicenes is strongly influenced by the substitution pattern in the helicene core that affects the mutual orientation of the monomeric units in the aggregated form. Thus, the 2,15-substituted derivative 1 undergoes an isodesmic supramolecular polymerization forming globular nanoparticles that maintain circularly polarized light (CPL) with glum values as high as 2 × 10-2. Unlike carbo[6]helicene 1, the 4,13-substituted derivative 2 follows a cooperative mechanism generating helical one-dimensional fibers. As a result of this helical organization, [6]helicene 2 exhibits a unique modification in its ECD spectral pattern showing sign inversion at low energy, accompanied by a sign change of the CPL with glum values of 1.2 × 10-3, thus unveiling an example of CPL inversion upon supramolecular polymerization. These helical supramolecular structures with high chiroptical activity, when deposited on conductive surfaces, revealed highly efficient electron-spin filtering abilities, with electron spin polarizations up to 80% for 1 and 60% for 2, as measured by magnetic conducting atomic force microscopy.

Positive-to-negative behavioural responses suggest hedonic evaluation in treefrog mate choice.

Sexual competition hinges on the ability to impress other conspecifics, to drive them away or attract them. In such cases, the selective environment may be hedonic or affective in nature, as it consists of the evaluations of the individuals making the decisions. This may contribute to the power of sexual selection because evaluations may range from positive to negative rather than simply from positive to neutral. Selection due to mate choice may therefore be stronger than currently appreciated. Further, change in preferred mate types can occur simply by changes (flips) in the evaluation of similar display features, adding to the dynamism of sexual selection as well as its strength. We tested the hypothesis of positive-to-negative behavioural responses in mate choice with a playback experiment using two treefrog species with 'mirror image' structures in their advertisement and aggressive calls. Female treefrog responses ranged from approach to evasion, and the presence of an aversive stimulus tainted evaluation of an attractive stimulus. Further, females in the two species showed flips in approach/evasion of stimuli with comparable signal structure. These results suggest that hedonic evaluation may have an important role in mate choice and showcase how mechanistic analysis can help understand evolutionary processes.

Planar Chiral Analogues of PRODAN Based on a [2.2]Paracyclophane Scaffold: Synthesis and Photophysical Studies.

We describe the synthesis and photophysical characterization of differently substituted planar chiral analogues of PRODAN based on a [2.2]paracyclophane scaffold. This experimental and theoretical study highlights that the (chir)optical properties of the new "phane" compounds, which incorporate an electron-withdrawing propionyl moiety and an electron-donating dimethylamino group at their para or pseudo-para positions, strongly depend on their substitution patterns. In particular, for this series of molecules, a more pronounced solvatochromism and clear chiroptical behaviors are observed when the two substituents are placed on the two rings of the pCp core in a non-"co-planar" arrangement (pseudo-para derivative). This observation may help design new pCp-based luminophores with finely tuned photophysical properties.